Surface force induced deformations: a post particle removal examination of the substrate

Micrometer size particles of tin and gold were deposited onto a polydimethylsiloxane/polyester alternating block copolymer substrate. After the adhesion induced deformations of the substrate equilibrated, the particles were removed by amalgamation with mercury and the substrate was examined using scanning electron microscopy. Craters having radii comparable to those of the particle/substrate contact zones [L. P. DeMejo, D. S. Rimai, J. Chen and R. C. Bowen, J. Adhesion 39, 61 (1992)] were observed. Elevated ridges around the craters were also observed, suggestive of tensile interaction induced menisci. Similar ridges were previously observed between the particles and the substrate. The occurrence of craters long after the removal of the particles suggests that the deformations are plastic rather than elastic. This is consistent with results reported earlier.